secondary storage battery

8/4/2019 secondary storage battery

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Lovely Professional University

TERM PAPER

CHEMISTRY CHE 101

TOPIC SECONDARY STORAGEBATTERIES

Submitted to: Submitted by:

Dr Gulshan Kumar Name Shailesh singhClass B.tech (ME)Section D4901Roll no. RD4901A59

Reg. No. 10908518

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ACKNOWLEDGEMENT

I am thankful to my teacherDr Gulshan Kumar for giving me this

opportunity. He trusted me and chose me for doing search on the topic

Secondary Storage Batteries. Though I have taken maximum

information from the internet but my friends and my books helped alot. This project has been prepared under the guidance of my

respected teacherDr Gulshan Kumar. Books are the best friends and

I have got lot of help from my text bookFundamental of Chemistry

by Raymond Chang. At last I would like to thank my mother without

whose support I would not have been able to make this project.

INDEX:-

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1 Batteries

02Types of batteries

03Construction of Primary and secondary cell

04Secondary or rechargeable batteries

05Its usage and application

06Types of secondary batteries

07Will secondary battery replace primary ones?

08Advantages of secondary batteries

09Application of secondary batteries

10Protection of secondary storage battery

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Batteries:

An electrical battery is a combination of one or more electrochemical cells, used to convertstored chemical energy into electrical energy. Since the invention of the first Voltaic pile in1800 by Alessandro Volta, the battery has become a common power source for manyhousehold and industrial applications. According to a 2005 estimate, the worldwide batteryindustry generates US$48billion in sales each year,[1] with 6% annual growth.[2]

Batteries may be used once and discarded, or recharged for years as in standby powerapplications. Miniature cells are used to power devices such as hearing aids andwristwatches; larger batteries provide standby power for telephone exchanges or computerdata centers. A battery is an energy storing system based on electrochemical charge/discharge

reactions. During discharge the chemical energy is converted into electrical energy and during chargethe energy is reconverted into chemical energy. In a primary battery system only the dischargereaction can be used. A secondary or rechargeable battery system is characterized by acharge/discharge reaction that is reversible.The higher the reversibility the more discharge/charge cycles can be performed. The electrical energystored in a battery is directly related to the chemical energy being stored. The cathode incorporatesan oxidizing material, the anode a reducing component. The laws of nature have fixed limits tospecific energy of electrochemical systems from the periodic table of elements:The maximum theoretical specific energy is attained for Lithium and Fluorine at 6,085 Wh/kg.However, most chemical reactions cannot be used in a battery system because they are notreversible in an electrochemical cell.

Batteries have to be distinguished from fuel cells and capacitors. A capacitor is based on a reversible separation

of charge with a significant lower energy, compared to a chemical reaction associated with a battery technology.Fuel cells convert chemical energy into electrical energy without the ability to be recharged by electrical power.Whenever energy has to be reversibly discharged and recharged at high energy density, and with highefficiency, a battery is the most suitable energy storage system.

Some batteries-

Duracell Lemon Battery Car Battery(used in torches) (used in cars)

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BL-5C Battery(used in mobiles)

Types of batteries:

Batteries are mainly classified into two types

Primary or non-rechargeable batteries

Secondary or rechargeable batteries

Primary Batteries-

Primary batteries are used once, then discarded. They have the advantage of

convenience and cost less per battery, with the down side of costing more over the

long term. Generally, primary batteries have a higher capacity and initial voltage than

rechargeable batteries, and a sloping discharge curve . Most primary batteries do not

presently require special disposal. The disadvantages of primary batteries are that it

is not suitable for high drain applications due to short life time and the cost of

continuous replacement.

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In terms of overall energy efficiency, single use, disposable, primary batteries are an

extremely uneconomical energy source since they produce only about 2% of the

power used in their manufacture.

Secondary Batteries-

The various types of battery power systems in AtoN services are Primary Batteries(nonrechargeable)and Secondary (rechargeable) batteries.Secondary (rechargeable) batteries01Lead-Acid batteries02Sealed (maintenance-free, valve-regulated) batteries03 Flooded electrolyte batteries (add-water type)04Nickel-Cadmium batteries05. Vented pocket-plate batteries06Vented sintered-plate batteries

07Sealed batteriesA number of countries are conducting trials with Nickel-Metal Hydride and Lithium-Ionbatteries. These are further defined in section 2.2 G. and 2 H.The choice of battery types will be made at the design stage. The following listings

outline the advantages and disadvantages of the majority of battery types in general use.

Secondary batteries are the rechargeable batteries. They have the advantage of being more

cost-efficient over the long term, although individual batteries are more expensive.

Generally, secondary batteries have a lower capacity and initial voltage, a flat discharge

curve, higher self discharge rates and varying recharge life ratings. Secondary batteries

usually have more active (less stable) chemistries which need special handling, containment

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and disposal. Ni-Cd and small-size lead acid batteries require special disposal and should

not be simply thrown away.

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Secondary storage battery diagrame......

.

In this project Im going to discuss more about secondary batteries.

Constructions of Primary and secondary cell:-

01 Primary Cell:-

The simplest of primary cells, the basis of batteries, is made from twoconductive metals, called electrodes, and solutions that contain thecorresponding metallic ions. Because of the reduction and oxidationreaction or redox as it is abbreviatedof these metals, which involves theloss and gain of electrons, current is able to flow through a wire from onemetal to the other. The metal where oxidation occurs is referred to as the

anode and the metal where reduction occurs is refer to cathode.

In figure Primary cellA salt bridge, comprised of a neutral solution, is placed between the two

solutions to balance the charges of the metal-solution system. We beganby constructing a simple primary cell from copper (Cu), copper (II) nitrate(Cu(NO3)2), zinc (Zn), and zinc nitrate (Zn(NO3)2), placing each metal in asmall container of its corresponding solution. After connecting the twosolutions with a salt bridge of potassium nitrate (KNO3), the cell wascomplete. The cell had a measurable voltage of approximately 1 V, butwas unable to power a small motor or light bulb because of the high

internal resistance caused by the salt bridge and nature of the cell. Weconstructed other primary cells made from the metals cadmium (Cd) and

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nickel (Ni) and the solutions cadmium nitrate (Cd(NO3)2) and nickel (II)nitrate (Ni(NO3)2), as well as the original materials, and tested the voltageand current of each combination. Like the Cu-Zn battery, however, eachcombination was unable to successfully power either the motor or thelight bulb and, while having a measurable voltage, did not have a

measurable current. Anode Cathode Measured Voltage ,did not have ameasurabule current.

Anode Cathode Measured voltageZinc Copper 0.942 VZinc Nickel 0.839 VZinc Cadmium 0.16 VNickel Copper 0.0804 VCadmium Copper 0.77 VCadmium Nickel 0.690 V

02.Secondary Cell

Unlike primary cells, secondary cells are able to be re-used multiple times.By supplying a certain amount of energy, we can force the chemicalreactions to occur in the reverse direction. In this way, secondary cells canbe recharged. Our group next constructed a simple lead-acid battery outof lead (Pb), pressed lead (IV) oxide (PbO2), and 1 mol/L sulfuric acid (1MH2SO4). The two electrodesthe solid Pb and pressed PbO2were placedin approximately 20-mL of 1M H2SO4 solution in a small crucible andconnected to a motor. However, due to its brittleness, the PbO2 repeatedlybroke off in the H2SO4 solution. The PbO2 electrode, due to its shape, alsoconstantly slipped into the solution, making it difficult to attach wires tothe electrode without the wires short-circuiting in the solution. Despiteattempts to wrap the wires in both tape and wax paper, the H2SO4 was stillable to make contact with the wires and cause short-circuiting in the cell.To solve this difficulty as well as to further reduce the amount of internalresistance in the cell, our group experimented making a paste-likematerial. Made from cornstarch and 1 M H2SO4, the paste enabled theelectrodes to not only be positioned closer together, which would help

maximize the voltage, but also made it easier for the ions in the reactionto move in comparison with the original solutions. While it made it easierto prevent the PbO2 electrode from slipping, the paste material failedtolower the internal resistance of the battery enough to power our motor.Hoping to reduce the internal resistance even more, we attempted todecrease the distance between the electrodes. By using dialysis tubing,the two electrodes were able to be broughtvirtually as close together aspossible while still not touching one another. The dialysis tubingalsoallowed ions to pass freely between the two electrodes, ensuring that thereactions would still take place. A sandwich type model consisting of thePb and PbO2 electrodes with the

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dialysis tubing wedged in between and taped all together solved theproblem of the PbO2 becoming totally submerged in the H2SO4 solution.However, the H2SO4 would slowly seep inbetween the electrodes, causing the wires that connected the electrodesto the motor to become

wet. Without surprise, the voltage was not measurable and the batteryfailed to run our motor

In figure secondary storage batteryTo eliminate the risk of short-circuiting the battery once again, our groupattempted to make a dry cell battery. Similar to the previoussandwich model, this next battery model consisted of the two electrodesglued together with the same paste of cornstarch and 1M H2SO4. This

model proved to be better than its predecessors. It was both easy toattach wires to the electrodes without having to worry about the batteryshort-circuiting and the internal resistance was successfully reduceddrastically. For once, there was a measurable resistance (jumpingbetween130 and 300 ) instead of the previous overload reading displayed forall of the other types ofbatteries. The voltage of this battery, 1.4 V, was also the highest one wehad read. Unfortunately,despite its drastic drop, the resistance was still too high for the battery toproduce enough current

needed to power the motor. After researching, our group realized thatinstead of using PbO2 as one electrode and Pb as the other, we could

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simply use two pieces of Pb as the electrodes. By first electrolyzing theH2SO4 solution, oxygen (O2) and hydrogen (H2) gases could be produced.The O2 that was produced then oxidized one of the Pb electrodes byplating it with PbO2. This process eliminated the problem of the PbO2breaking apart in the H2SO4 solution as well as it slipping into the beaker.

Because Pb is very malleable, it was easy to bend the electrodes so thatthey would fasten to the sides of the beaker without slipping which solvedthe difficulty of attaching the wires to the electrodes without coming incontact with the sulfuric acid solution. Using a direct-current adaptedpower supply, we first charged the cell for five minutes. Instantly theanode became a distinct brown colour, signifying that it was becomingplated with PbO2, and the H2SO4 began bubbling, indicating the productionof O2 and H2 gases. Because of the alternate current that was being used,the bubbles looked as if they were pulsating; however there seemed to beno adverse effects in this phenomenon. After five minutes, the cell wasdisconnected from the power supply and hooked up to a small motor.Though for only a few seconds, the motor successfully ran for the firsttime. The cell also had a voltage of around 1.8 Vthe highest voltageachieved although it dropped at a rate of approximately -0.005 V/sec.

We reconstructed the cell, with the two lead electrodes suspended in asolution of H2SO4, to test how the surface area and distance between theelectrodes and the molarity, or concentration, of the sulfuric acid solutionaffected the voltage and motor run time of the cell as well as how well thecell retained its charge after being charged for five minutes using a 9 Vbattery. These results can be seen located below.

Electrode Distance (cm)Motor Runtime (s)Standard 5.58.0Variation One 1.08.0

Variation Two N/A (electrodes separated11.0

using dialysis tubing)

Note:- Both experiments done in 160-mL of 3 M H2SO4 with electrodes ofsurface area of4.47 cm2 and 4.04 cm2.

The distance between the electrodes has an inverse relationship with themotor run time and power output although the actual effect of decreasingthe distance between the electrodes was minimal. The one visibledifference of decreasing the distance between the electrodes was thatdoing so made the reactions occur at a faster rate and the motor run

faster and smoother; during variation one, the motor would start and stop

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a couple times whereas in variation two the motor ran constantly with nointerruptions.

Anode Anode Cathod CathodMotor

Dimensions Surface Area Dimension Surface

area Runtime(cm) (cm.cm) (cm)

(cm.cm) (s)Standard 3.15x0.6x0.1 4.47 2.8x0.60.14.04 8.0

Variation 2.8x3.8 21.28 2.6x3.819.76 11.2

One (height insignificant) (hight significant)

Note: - Both experiments done in 160-mL of 3 M H2SO4 with electrodes5.5 cm apart.

The surface area of the electrodes has a direct relationship with the motorrun time but like distance, the effect was negligible in the lead storagebattery. One observation made during thecharging was that during variation one the production of hydrogen gasgreatly increased, as wellthe speed of the motor, similar to decreasing the distance of the

electrodes. When the surface to area was increased in the iron storagebattery, the motor runtime increased greatly.

Molarity Motor Runtime(M/L) (s)

Standard 3.00 11.2

Variation one 1.00 21.0

Variation two 0.50 37.0

Variation three 0.25 39.0

Note:- All experiments were done using lead electrodes with surface areaof 21.28 cm2 and 19.76 cm2 at a distance of 5.5 cm apart.

The molarity of the H2SO4 has an indirect relationship with the motor runtime and had the most significant effect on it. However, while the motorruntime did increase with decreasing molarity, the power output of the

battery decreased as well, i.e. the motor ran at a slower speed but for alonger period of time.

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Wait Time Motor Runtime(min) (s)

Standard 0.0 39.0

Variation One 30.0 24.8

Note:- Both experiments were done in 160-mL of 3 M H2SO4, using Pbelectrodes with surface area of 21.28 cm2 and 19.76 cm2 at a distance of5.5 cm apart.

The cell lost approximately half a second of motor run time with eachminute that passed.Thus, it would be completely discharged after 80 minutes.

Molarity VoltageCurrent

(mol/L) (V)(mA)

Standard 6.00 2.150.21Variation One 3.00 2.061.63Variation Two 1.00 1.851.87Variation Three 0.50 2.05

1.68Variation Four 0.25 2.051.39

Note:- All experiments were done using Pb electrodes with surface area of21.28 cm2 and19.76 cm2 at a distance of 5.5 cm apart.

Because H2 gas explodes in the presence of a flame, we thought it wouldbe best to eliminate,or at least reduce, the amount that was being produced. Instead of usinga H2SO4 solution, the

test cell used the H2SO4 paste that had been used in many other testsmade from 6 M H2SO4 and cornstarch. While significantly less thanpreviously, there was still a noticeable amount of bubbles, and thereforeH2 gas being formed, but with proper ventilation, this small amount canquickly disperse and the risk of an explosion eliminated, should there be afire nearby.

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Secondary or rechargeable batteries-

A secondary battery (also known as rechargeable orstorage battery) is a group of one or

more electrochemical cells. They are known as secondary cells because theirelectrochemical

reactions are electrically reversible.

Secondary batteries or rechargeable batteries contain active materials that can be regenerated

by charging. When the energy produced by rechargeable batteries drops below optimum

efficiency, secondary batteries may be recharged in a couple of ways, depending upon their

construction.

In the United States, secondary batteries carry designations such as AAAA, AAA, N, 1/3 AA,

2/3 AA, AA, 1/2 A, 2/3 A, A, 4/5 Cs, Cs, C, 1/2 D, and D. Nonstandard rechargeable

batteries or secondary batteries include prismatic cells, coin or button cells, sachet cells,

lantern batteries, and battery packs.

Charging of secondary batteries

A method of charging a battery includes applying a charging current from a

semiconductor device to the battery during a first battery charging time period. Themethod also includes measuring a charging voltage level at the battery during the

first battery charging time period. During a non-charging voltage measurement time

interval, the method includes temporarily stopping application of the charging current

from the semiconductor device to the battery and measuring a non-charging voltage

level at the battery while the charging current is not being applied to the battery.

During charging, the positive active material is oxidized, producing

electrons, and the negative material is reduced, consuming electrons.

These electrons constitute the current flow in the external circuit. The

electrolyte may serve as a simple buffer for ion flow between the

electrodes, as in lithium-ion and nickel-cadmium cells, or it may be an

active participant in the electrochemical reaction.

Rechargeable batteries are susceptible to damage due to reverse

charging if they are fully discharged. Fully integrated battery chargers

that optimize the charging current are available.

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http://en.wikipedia.org/wiki/Battery_(electricity)http://en.wikipedia.org/wiki/Electrochemical_cellhttp://en.wikipedia.org/wiki/Electrochemistryhttp://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Oxidizedhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electrical_networkhttp://en.wikipedia.org/wiki/Electrolytehttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Electrodehttp://en.wikipedia.org/wiki/Lithium-ion_batteryhttp://en.wikipedia.org/wiki/Nickel-cadmium_batteryhttp://en.wikipedia.org/wiki/Electrochemicalhttp://en.wikipedia.org/wiki/Rechargeable_battery#Reverse_charginghttp://en.wikipedia.org/wiki/Rechargeable_battery#Reverse_charginghttp://en.wikipedia.org/wiki/Battery_chargerhttp://en.wikipedia.org/wiki/Battery_(electricity)http://en.wikipedia.org/wiki/Electrochemical_cellhttp://en.wikipedia.org/wiki/Electrochemistryhttp://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Oxidizedhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electrical_networkhttp://en.wikipedia.org/wiki/Electrolytehttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Electrodehttp://en.wikipedia.org/wiki/Lithium-ion_batteryhttp://en.wikipedia.org/wiki/Nickel-cadmium_batteryhttp://en.wikipedia.org/wiki/Electrochemicalhttp://en.wikipedia.org/wiki/Rechargeable_battery#Reverse_charginghttp://en.wikipedia.org/wiki/Rechargeable_battery#Reverse_charginghttp://en.wikipedia.org/wiki/Battery_charger


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Usage and application-

Secondary batteries currently are used for applications such as automobile starters, portable

consumer devices, light vehicles (such as motorized wheelchairs, golf carts, electric bicycles,

and electric forklifts), tools, and uninterruptible power supplies. Emerging applications in

hybrid electric vehicles and electric vehicles are driving the technology to reduce cost, reduce

weight, and increase lifetime.

Unlike non-rechargeable batteries (primary cells), rechargeable batteries have to be chargedbefore use. The need to charge rechargeable batteries before use deterred potential buyerswho needed to use the batteries immediately. However, new low self discharge batteriesallow users to purchase rechargeable battery that already hold about 70% of the ratedcapacity, allowing consumers to use the batteries immediately and recharge later.

Grid energy storage applications use industrial rechargeable batteries for load leveling, wherethey store electric energy for use during peak load periods, and forrenewable energy uses,such as storing power generated fromphotovoltaic arrays during the day to be used at night.By charging batteries during periods of low demand and returning energy to the grid during

periods of high electrical demand, load-leveling helps eliminate the need for expensive

peaking power plants and helps amortize the cost of generators over more hours of operation.

Types of secondary batteries-

Rechargeable batteries can be divided into two main classifications based upon theirchemical composition: alkaline secondary batteries and lithium secondary batteries. Bothclassifications include an assortment of battery styles. Common alkaline rechargeable

batteries include nickel-cadmium batteries, nickel-zinc rechargeable batters, nickel-iron

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batteries, silver oxide batteries, sealed nickel-hydrogen secondary batteries, and nickel-metal hydride rechargeable batteries.

Nickel is a common material in rechargeable batteries or secondary batteries. Nickel-cadmium, nickel-zinc, and nickel-iron are the most common alloys. Nickel-cadmium batteries(Ni-Cd) are popular, but have a relatively low capacity. Nickel-zinc batteries are

characterized by a high specific energy and power capability. Nickel-zinc batteries (Ni-Zn)provide energy for electric vehicles such as small vans and passenger cars. Nickel-ironbatteries (NiFe) are the most important commercial rechargeable system that uses ironelectrodes. They are nearly indestructible, have a long life, and can withstand electricalabuse (overcharge, overdischarge, short-circuiting, etc.). These rechargeable batteries orsecondary batteries generally cost more than lead acid batteries, but have a low cell voltage,low power density, and lower energy density than competitive systems.

Silver oxide batteries, sealed nickel-hydrogen batteries, and nickel-metal batteries are alltypes of alkaline rechargeable batteries (alkaline secondary batteries). Silver oxide (AgO)batteries are noted for their high energy density and power density. Silver electrodes areexpensive, however, which limits their use. Silver-zinc cells have the highest energy per unit

weight and volume. Sealed nickel-hydrogen secondary batteries (Ni-H2) are a hybrid thatcombines battery and fuel-cell technologies. They have a long cycle life, high specificenergy, high power density, and tolerance for electrical abuse. Nickel-metal hydride (NiMH)rechargeable batteries are interchangeable with most nickel-cadmium secondary batteries(NiCd). Nickel-metal hydride batteries generally deliver 10 to 25% greater capacity than

NiCds, and are more environmentally friendly since they do not contain cadmium.

Will secondary batteries replace primary ones?

Consumer market put aside, the largest users of primary (non-rechargeable) batteriesare the military, specialty emergency services and forest fire fighters. High energydensity, long storage and operational readiness are among their strong attributes. Nocharging and priming is required before use. Logistic is simple and battery power can be

made available at remote locations that are unmanned and have no electrical power.Disposal is easy because most primary cells contain little toxic materials.

Primary batteries have the highest energy density. Although the secondary

(rechargeable) batteries have improved, a regular household alkaline provides 50%more power than lithium-ion, one of the highest energy-dense secondary batteries. Theprimary lithium battery used in cameras holds more than three times the energy of a

lithium-ion battery of same size.

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Figure 1: Energy comparison of rechargeable and non-rechargeable batteries.

The negative on the primary batteries is its relative high internal resistance,which inhibits current flow. High internal resistance has little affect when

powering low-current devices such as a TV remote control or a kitchen clock. Theproblem arises with digital cameras and other power-hungry devices. A powerdrill on an alkaline would be unthinkable. The voltage would imply collapse.

Reverse charging of rechargeable batteries:

Reverse charging, which damages batteries, is when a rechargeable battery is recharged with

itspolarity reversed. Reverse charging can occur under a number of circumstances, the two

most important being:

When a battery is incorrectly inserted into a charger.

When multiple batteries are used in series in a device. When one battery completely

discharges ahead of the rest, the other batteries in series may force the discharged

battery to discharge to below zero voltage.The active components in a secondary cell are the chemicals that make up the positive and

negative active materials, and the electrolyte. The positive and negative are made up of

different materials, with the positive exhibiting a reduction potential and the negative having

anoxidation potential. The sum of these potentials is the standard cell potential orvoltage.

Inprimary cells the positive and negative electrodes are known as the cathode and anode,

respectively. Although this convention is sometimes carried through to rechargeable systems

especially with lithium-ioncells, because of their origins in primary lithium cellsthis

practice can lead to confusion. In rechargeable cells the positive electrode is the cathode ondischarge and the anode on charge, and vice versa for the negative electrode.

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Advantages of secondary batteries:

Greater efficiency and performance

Rechargeable batteries can be recharged up to 500 times! This results in far greater costand power efficiency per battery compared to alkaline batteries.

Rechargeable batteries will outperform the best alkalines in high-drain appliances suchas digital cameras. Rechargeable technology has greatly improved over the years and isnow leading the way for camera enthusiasts who require performance and reliability.

Convenience

With rechargeable batteries, you no longer have to remember to buy new batteries. Justimagine if you could not charge your GSM (mobile phone) battery. You would have togo shopping several times a week to buy a new battery.

By having just 2 sets of rechargeable batteries you can have a spare set ready to use allthe time so you will never run out! Rechargeable batteries will replace ordinary batteriesin almost any appliance.

They are of the same size as conventional batteries and are ideal for solicited or "energy-consuming" devices such as a Walkman, a portable CD player, digital cameras, radiocassette players, remote guided toys, electronic games, portable telephones, electricrazors

Additional convenience through in-car chargers

Uniross has allowed rechargeable battery users to recharge their batteries whilst on themove! In-car chargers provide batteries with power as and when required. Who knows when

batteries will suddenly lose their power when its most needed? Taking the power from thecars battery means that rechargeable batteries are on hand whenever they are required!

Environment

Using rechargeable batteries reduces household waste. 15 billion ordinary batteries arethrown away every year, all of which end up in landfill sites. Rechargeable batteries can be

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reused which helps reduce the impact disposable batteries have on the environment.

The most ecological rechargeable batteries are Ni-MH rechargeable units (Nickel-metalhydride).

Categories for Application of Secondary Batteries:-

The applications of the secondary batteries may fall into two main categories:

0A First Category :- those applications in which the secondary battery is used ordischargedessentially as a primary battery, but recharged after use rather than being discarded.Secondary batteries are used in this manner for convenience, for cost savings (as they can brecharged rather than replaced), or for applications requiring power drains beyond the

capability of primary batteries.

0B Second Category :- those applications in which the secondary battery is used as anenergy-storage device, generally being electrically connected to and charged by a

prime energy source, and delivering its energy to the load on demand when theprime energy source is not available or is inadequate to handle the loadrequirement.

MAJOR ADVANTAGES AND DISADVANTAGES OF VARIOUSTYPES OF BATTERY:-

0A LEAD-ACID BATTERIES (compared with other electrochemical batteries)

Advantages:-

01. Popular low cost secondary battery capable of manufacture on a local basis,worldwide, from low to high rates of production

02 . Available in large quantities and in a variety of sizes and designs manufactured in sizesfrom smaller than 1 Ah to several thousand ampere hours.

03. Good high-rate performance

04 . Electrically efficient turnaround efficiency of over 70 %, comparing discharge energyout with charge energy in

05. High cell voltage (open-circuit voltage of 2.0 V is the highest of all aqueouselectrolyte battery systems)

06. Good float charge service07. Easy state-of-charge indication (only wet electrolyte)

08. Low cost compared with other secondary batteries.Disadvantages:-

01.Relatively low cycle life (50 500 cycles), up to 2000 cycles with specil designs

02. Limited energy density typically 30 40 Wh/kg.

03.Poor low- and high-temperature performance.

04. Poor charge retention.

05. Long-term storage in a discharged condition can lead to irreversible polarization ofelectrodes.

06.Hydrogen evolution can result in an explosion hazard.07. Thermal runaway in improperly designed batteries or charging equipment.

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08.Positive post blister corrosion with some designs.

09.An intolerance to deep discharging resulting in Sulphation of plates and battery failure.0BVALVE-REGULATED LEAD-ACID (VRLA) BATTERIES

Advantages:-

01. Maintenance-free

02. Long life on float service

03. High-rate capacity

04. High charge efficiency

05. No "memory" effect (compared to nickel-cadmium battery)

06. "State of charge" can be determined by measuring voltage

07. Low cost

08. Available from small single-cell units (2 V) to large 24 V batteries.Disadvantages:-

01. Cannot be stored in discharged condition

02.Relatively low energy density

03.Lower cycle life than sealed nickel-cadmium battery.

04. Hydrogen evolution can result in an explosion hazard.

05.Thermal runaway in improperly designed batteries or charging equipment

06.Poor low- and high-temperature performance

07.An intolerance to deep discharging resulting in Sulphation of plates and battery failure.

0C ABSORBED MATT GLASS BATTERIES (AGM)

Advantages:-

01. Non-spill (absorbed electrolyte)

02. High rate charging

Disadvantages:-01. As per lead-acid batteries

02.Higher cost0D VENTED (INDUSTRIAL) NICKEL-CADMIUM BATTERIES (POCKET

PLATE)

Advantages:-

01. Excellent reliability

02.Good charge retention

03.Can tolerate deep discharge which enables the use of total battery capacity

04. Good high and low temperature performance

05. Excellent long-term storage (in any state of charge)06.Low maintenance

07.Absence of corrosive attack of the electrolyte on the electrodes and other components inthe cellDisadvantages:-

01 Hydrogen evolution can result in an explosion hazard

02Thermal runaway in improperly designed batteries or charging equipment

03 Low energy density

04 Higher initial cost than lead-acid batteries.E. VENTED-SINTERED-PLATE NICKEL-CADMIUM BATTERIES

Advantages:-01.Flat discharge profile

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02.Higher energy density (50 % greater than pocket plate)

03.Superior high-rate and low-temperature performance

04.Rugged, reliable, little maintenance required

05.Excellent long-term storage in any state of charge and over a very broad temperaturerange (-60 C to +60 C)

06. Good capacity retention; capacity can be restored by rechargeDisadvantages:-

01. Hydrogen evolution can result in an explosion hazard

02. Thermal runaway in improperly designed batteries or charging equipment

03. Contains cadmium, which may increase cost of disposal depending on recyclingfacilities available.

04.Higher initial cost .

05.Memory effect (voltage depression) if not periodically deep cycled.

06.Temperature controlled charging system required to enhance life.

Physical protection of secondary storage battery:-

Physical protection needs to be provided against consequences of adverse site conditionsand handling, for example, against effects of1. temperature gradient and extremes of temperature,2. exposure to direct sun light (UV radiation),3. airborne dust or sand4. explosive atmospheres5. high humidity and flood water6. earthquakes

7. shock, spin, acceleration and vibration (particularly during transport, and lightbuoy applications)8. several mechanical abuse and rough handling.

01 Capacity:-The storage capacity is expressed in ampere-hours (Ah) and varies with the conditions ofuse (electrolyte temperature, discharge current and final voltage). Normally the ratedcapacity for 10 h and 5 hours discharge, respectively, is published. The knowledge of thecapacity for a 100 hours (C100 ) discharge time is also required as these times are commonlyused in PV applications.

02 Cycle Life:-The cycle life (endurance) is the ability of the battery to withstand repeated charging and

discharging. The cycle life is normally given for cycles with a fixed depth of discharge(DOD) and with the battery fully charged in each cycle. Batteries are normally characterized

by the number of cycles that can be achieved before the capacity has declined to the valuespecified in the relevant standards (e.g. 80 % of the rated capacity). In photovoltaicapplications the battery will be exposed to a large number of shallow cycles but at a varyingstate of charge. The batteries should therefore comply with the requirements of the testdescribed in IEC 61427, which is a simulation of the PV system operation. Themanufacturer should specify the number of cycles the batteries can achieve before thecapacity has declined to 80 % of the rated capacity.

03 Charge control:-

To maintain optimum performance of a battery it is essential that its charge is properlycontrolled. Ideally the charge current should be limited at the start of the charge cycle to

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ensure that gassing does not occur due to excessive applied cell voltage; while the rechargecapacity is being restored the charge current should be limited to maintain the cell voltage tothat, or just below that required for gassing; once the full discharge current has been restoreda finish charge at constant current should be applied for a fixed time period. Whilst theseconditions may not be practically achieved in PV energy systems, there are certain

conditions that need to be addressed in order to minimise maintenance and maintain batterylife. The parameters of the regulator should take into account the effects of the PV generatordesign, the load, the temperature and the recommended limiting values for the battery. Wetlead-acid or nickel-cadmium batteries should have sufficient electrolyte to cover at least the

period between planned service visits. Excessive overcharge does not increase the energystored in the battery. Instead, overcharge affects the service interval due to waterconsumption in wet lead acid batteries as a result of gassing. To minimise this effect thecharge / regulation voltage should be compensated for changes in battery temperature sincethis has a direct affect on the gassing voltage threshold. Contrary to this, stratification canoccur in wet lead acid batteries, particularly in PV systems where insulation is ofteninsufficient to provide regular gassing during normal operation. Stratification is where the

electrolyte settles.

04 Charge retention:-Charge retention is the ability of a battery to retain capacity during periods of no charge,when not connected to a system, during transportation or storage. A battery for PVapplication should show a high capability of charge retention. The charge retention should

be stated by the manufacturer and should meet the requirements of the relevant batterystandard,

05. Over discharge protection:-Lead-acid batteries should be protected against over discharge to avoid capacity loss dueto irreversible sulphating. This can be achieved by low voltage disconnect that operates

when the design maximum depth of discharge is exceeded..

06. Mechanical endurance:-Batteries for PV application should be designed to withstand mechanical stresses duringnormal transportation and rough handling. Additional packing or protection may be requiredfor off road conditions. Batteries for PV application on light buoys should be chosen towithstand shock, vibration and acceleration as the light buoy can be subject to violentmovement. The battery design should prevent any electrolyte leakage and an adequateventing arrangement provided to enable any gas generated to escape but to prevent water

06.Recycling and Disposal:-Laws and regulations governing the recycling and disposal of batteries are getting stricterevery year. In many countries, batteries are considered hazardous waste. The heavy metalsused in these batteries, when improperly disposed of, will damage the environment; thecorrosive nature of battery electrolytes can also cause damage if released. While lithium

batteries pose little pollution risk they must still be disposed of as hazardous waste becauseof their history of explosive venting in various circumstances. Lead-acid and nickel-cadmium batteries are recyclable in most countries, although restrictions on nickel-cadmiumrecycling appear to be increasing, along with the associated costs. Every effort should bemade to handle these batteries correctly when it comes time to dispose of them, in mostcountries, strict laws govern the handling of hazardous waste. In addition detailed recordsmust be maintained to account for the

Where about of batteries during all phases of disposal. Reputable transporters are used toensure that the material ends up at the destination and not by the wayside. The first point of

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contact for establishing disposal arrangements should be the battery vendor.

04 Safe handling of batteries:-Batteries are an integral part of any solar, wind or hybrid power system used in aids tonavigation, yet little has been written on their safety, installation, maintenance, recyclingand disposal.

05 Battery Safety Issues:-Large battery systems are a source of extremely high short circuit currents. Care must beexercised when installing and servicing any of the components in the power system to

prevent shorting. Secondary batteries generate hydrogen gas during the charging process.Significant amounts of hydrogen gas are generated when the battery reaches full charge.Hydrogen gas ignites easily and produces an especially violent explosion. Accordingly, thefollowing safety precautions should be observed at all times.(a) Do not smoke, use an open flame or create arcs or sparks in the vicinity of the battery.(b) Sense the interior of a battery enclosure with a suitable gas detector before entering. Thecompartment should have a removable, non-sparking pipe fitting for insertion of a sensor

probe.(c) Ventilate the enclosure (leave doors open) for at least 5 minutes before servicing thebatteries.(d) Discharge static electricity from the body before touching the cells by touching agrounded surface such as a conduit.(e) Hydrometers for nickel-cadmium and lead-acid batteries must be kept separate and notinterchanged.

06 Ventilation:-Lead-acid and nickel-cadmium batteries produce hydrogen and oxygen gas when charging.Secondary batteries that employ recombination features will only gas when the gassing rateexceeds the recombination rate. This generally occurs during overcharge. Batteries without

recombination features will gas when they are fully charged and continue to receive a charge(float condition). The amount of hydrogen and oxygen evolved is not dependent on the typeand size of battery (lead-acid or nickel-cadmium), but rather on the charging rate, number ofcells and the length of time charge is applied. Hydrogen and oxygen are produced as a resultof electrolysis of the water in the electrolyte. Hydrogen concentrations of up to 3% (byvolume) are non-flammable, at 4- 8% hydrogen will burn if exposed to an open flame orspark, and above 8% hydrogen will ignite explosively. Hydrogen can also be produced in

battery pockets by reactionbetween residual water and dissimilar metals or corrosion of metals by spilled electrolyte.The maximum hydrogen concentration for an enclosed space set by the Occupational andSafety Health Act (OSHA) in the USA is 1%. Check with your department which regulatesworker safety or fire protection for acceptable limits in your country. Some countries havesubstantially lower limits. Some batteries also release small quantities of toxic gases.However, calculating theventilation requirements based on the predominant gas, hydrogen, will maintain these gases

below their toxic limits. Hydrogen production for lead-acid and nickel-cadmium standardsshould be complied with:H = 0.459 x N x IWhere:H is the amount of hydrogen produced in I/hr (litres/hour); 0.459 I/hr is the maximumhydrogen production per cell per ampere charge current at standard temperature and

pressure; N is the number of cells; I is the estimated charge current. The charge current forthe battery must be determined. Battery manufacturers can provide information on gassing

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rates for their batteries. Be aware that some batteries, especially lead-antimony, will gas at ahigher rate as they age, and as the battery temperature rises above nominal (usually 25degrees C). Short of this, a general rule of thumb is that the float current will not exceed one

percent (0.01) of the rated capacity inAmpere-hours. This rule of thumb does not account for charger failure, which could charge

the battery at a rate higher than one percent of the rated capacity. While this type of failureis rare, it is wise to see if the factor of safety between the maximum concentration level (see

below) and the lower flammable limit (4 percent) can accommodate the excess hydrogenproduction. Hydrogen detectors or overvoltage alarms tied to telemetry systems can provideadvance warning of dangerous levels of gas. Installation of such warning systems inenclosed compartments in aids to navigation Knowing the amount of hydrogen produced,the amount of new air required to prevent the concentration from exceeding the

predetermined level can be calculate:A = H/C Where:A is the amount of new air required in I/hr;H is the amount of hydrogen production in I/hr;

C is the maximum concentration level as a decimal.Next, the size of the battery enclosure or room must be calculated. For larger systemsashore, manufacturers of Modular rooms may be able to provide information on naturalair change rate. On converted dwellings, a tight battery room will have an air exchange inabout 4 hours. Therefore, as an example, if we require 8000 I/hr of new air, then the batteryroom must have a volume of at least 32000 litres if no vent system is installed. If additionalventing is required, then the preferred type is a low mounted louvered vent in the door orwall and a ridge vent (to expel hydrogen trapped near the ceiling) at the highest point in theshelter.

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REFFERENCES:-

www.nikon.co.in/products.php?categoryid=57

www.azsolarcenter.org/tech.../battery-handbook-for-pv-systems.html

www.tutorvista.com/topic/advantages-of-secondary-storage-battery

Fundamental of Chemistry by Raymond Chang

Advanced Physical Chemistry

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http://www.nikon.co.in/products.php?categoryid=57http://www.azsolarcenter.org/tech.../battery-handbook-for-pv-systems.htmlhttp://www.azsolarcenter.org/tech.../battery-handbook-for-pv-systems.htmlhttp://www.azsolarcenter.org/tech.../battery-handbook-for-pv-systems.htmlhttp://www.azsolarcenter.org/tech.../battery-handbook-for-pv-systems.htmlhttp://www.azsolarcenter.org/tech.../battery-handbook-for-pv-systems.htmlhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-batteryhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-batteryhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-batteryhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-batteryhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-batteryhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-batteryhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-batteryhttp://www.nikon.co.in/products.php?categoryid=57http://www.azsolarcenter.org/tech.../battery-handbook-for-pv-systems.htmlhttp://www.tutorvista.com/topic/advantages-of-secondary-storage-battery


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